1. Field of the Invention
The present invention teaches an improved flexible medium for a scrolling-type color changer. More specifically, the present invention defines a color changer medium with continuously-variable characteristics across its length.
2. Background Information
Stage lighting systems project a beam of light which has been colored by a color filter. Different ways of coloring the light are known.
One way of coloring the light is by using dichroic filters such as taught in U.S. Pat. No. 4,800,474. This technique mounts a number of dichroic filters on rotatable color wheels. This system needs a large amount of space because the wheels must each have room for many filters to allow enough colors, and there must be room for the wheels to rotate.
Another way of coloring the light is by using a scrolling-type color changer such as that shown and described in U.S. Pat. No. 5,126,886, the disclosure of which is herewith incorporated by reference. Scrolling color changers move material between two scrolls to provide a desired filtering effect within the light path.
A problem occurs in determining how to appropriately change the color across the length of the color media of a scrolling changer. U.S. Pat. No. 5,126,886 demonstrates one conventional method of changing the color saturation across the length of the filter. A filter material is formed with a baseline saturation. A half-tone pattern is located thereon. This half-tone pattern provides a filtering effect which can be changed by adjusting the number of patterned elements per unit area.